Carbureter.



W. SHAKESPEARE, 1R. L W. SCHMID.

CARBURETER.

APPLICATION FILED DEc.12,1914.

1,243,348 A Patented Oct. 1G, 15H7.

73.01% fdd/m l Grumman W, SHM SPE/WE, 1R. iL W, SCHNHD.

CARBURETER.

APPLlcATIoN FILED DEc.12,1914.

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WILLIAM- SHAKESPEARE, JR., ANI) WILLIAM SCHMID, OF KALAMAZOO, MICHIGAN, ASSIGNORS TO WILLIAM SHAKESPEARE, JR. COMPANY, OF KALAMAZOO, MICHIGAN.

CARB'URETER.

Specication of Letters Patent.

Patented Oct. in, '191 Application-med December 12, 1914. Serial No. 876,885.

To all lwhom t may concern:

Be it known that we, WILLIAM` SHAKE- srnARE, Jr., and WILLIAM SCHMID, citizens of the United States, residing in the city and county of Kalamazoo, State of Michigan, have invented certain new and useful Improvements in l(Qarbureters, of which the following is a specification.

This invention relates to improvements in carbureters.

In the operation of internal combustion engines, it is desirable to havea uniformly proportioned mixture of air and fuel supplied to the engine by the carbureter throughout the'range of engine speeds. Heretofore cams and levers and other mechanisms have been used for operating straight or uniformly tapered needle fuel valves in connection with the air valve of a carbureter in an attempt to secure such a uniformity of mixture. Adjustable springs have also been used in combination with the air valve to control the relative flow of air to the fuel.

It is the main objects of oui` invention to provide in a carbureter an improved means for maintaining the uniformity of mixture of fuel and air throughout the varying speeds of the engine by means of a fuel valve which harmonizes the flow of fuel to the air; and to provide an improved' carbureter adapted to accomplish these results without resorting to the use of means for relatively adjusting the needle to the air valve in the normal operation of the valves.

Further objects, and objects relating to structural details, will definitely appear from the detailed description to follow.

We accomplish the objects of our invention Yby the devices and means described in the following specification. The invention is clearly defined and pointed out in the claims.

A structure which is a preferred embodiment of our invention is clearly illustrated in the accompanying drawing forming a part of this specification, in which:

Figure I is a detail side elevation of a structure embodying the features of our invention, parts being illustrated in vertical central section.

Fig. II is an enlarged detail view ofthe fuel nozzle and valve, the nozzle being shown in vertical central section, the valve being shown closed or seated, the 'outlines of a uniformly orstraight tapered valve of the same dimensions being indicated by. dotted lines.

Fig. III is a view of the parts shown in Fig. II with the valve in its quarter open position.

Fig. IV is a view of the parts shown in Fig. II with valve shown in its half open position.

Fig. V is a view of the parts shown in Fig. II with valve in its three quarter open position.

Fig. VI is a view of the parts shown in Fig. II with valve in its fully opened posit1on.

Fig. VII is a diagram illustrating the variation in portage of our improved fuel valve of given dimensions during a complete movement thereof in comparison with variation in portage of a uniformly or straight tapered needle of the same dimensions.

Fig. VIII is an illustrative view greatly enlarged and somewhat distorted in order to better illustrate the details of our improved valve, the dimensions of a valve such as we commonly employ in a medium sized carbureter and the center and radius of the arc of the curved taper of the valve being indicated.

Fig. IX is a detail view partially in vertical central section of a modified form of carbureterembodying the features 'of our inventlon.

In the drawings similar reference numerals refer to similar part-s throughout the views.

In Fig. I of the accompanying drawings we` have illustrated our present improvements embodied inca structure substantially as described in our application for Letters Patent filed July 22, 1914, Serial No. 862,350. We, however, only illustrate and describe such details of the carbureter mechanism as will enable the clear understanding of our present improvement and its practical adaptation and embodiment.

The carburetor body l is provided with a suitable fuel reservoir not shown and is chambered or provided with a passage. In this passage is the throttle or air valve seat 2, the part of the passage above the valve seat constituting the mixing chamber and delivery passage 4 of the carbureter.

The air valve 5 -coacts with the valve seat 2. The air valve 5 is provided with a carbureting chamber 6 which delivers through the ports 7 into the mixing chamber above the valve.

The nozzle S is connected to the fuel reservoir by the passage 9 and projects upwardly into the carbureting chamber 6. The nozzle 8 has a reduced portion 10 at its upper end with which the annular carbureting chamber valve 11 coacts. This carbureting chamber valve 11 is mounted within the mixing chamber and is preferably conical as shown.

Below the valve 11 is a sleeve part 12 slidably embracing the nozzle and provided with a series of air inlet openings 13. The throttle valve is carried by the main actuating member 14 which is mounted for longitudinal movement in the carbureter body. The fuel valve 15 projects into the nozzle 8 and coacts therewith to control the delivery of the fuel. The main actuating member 14 is provided with a rack 16 with which the pinion 17 on the shaft 18 coacts. The operating means for the pinion shaft are not shown.

The actuation of the actuatingmember 14 opens and closes the throttle valve and also.

the carbureting chamber valve and the fuel valve. To adjust the fuel valve relative to the throttle valvewe provide an adjusting screw 20 against which the valve is held by the coiled spring 21 seated in the adjustable member 22 in the upper end of the main actuating member 14. This member' 22 is provided with means for raising and lowering the fuel valve independently of the throttle t"valve against the tension of the spring 23 but as the details of this means are fully described in our co-pending application referred to and form no part of the present invention, they are not further described herein.

The fuel valve 15 is provided with va tapered needle point 24 having an inward longitudinal curvature, the curvature being an arc of a circle whose center is adjacent to and preferably below a plane through the needle point and the valve seat when the valve is fully opened. This we have illustrated in Fig. VIII of the accompanying drawing.

This figure shows a valve greatly enlarged and somewhat distorted. The dimensions indicated in the figure are those of a valve such as we commonly use and find satisfactory and for medium sized carbureters. These dimensions are .055 of an inch at seating point, .032 of an inch at the fully opened or limit of movement point. the scope of movement being .250 of an inch. The radius of the arc of curvature in such a valve is preferably 8 inches and the center of the arc is .242 of an inch below the plane of the upward limit of movement or fully opened point. In Fig. III, we show the valve fully seated. It will be understood, however, that in practice, the valve is not completely seated in its normal closed position but is slightly open or slightly raised from its seat as is the common practice in carbureters of this type. The Figs. II to VI are all greatly enlarged and somewhat distorted in order that the features may be more clearly illustrated.

In Figs. III, IV, and VI, we show the valve in its quarter, half, three-quarter and fully open positions respectively. We also indicate by the dotted lines 26 the outlines of a uniformly tapered needle of the same dimensions, such dotted lines being present on each of Figs. II to VI.

To assist in understanding the result obtained by our improvements, we represent a diagram in Fig. VII showing the comparative time in seconds required to pass 10 cu. in. of commercial gasolene of 68 BaumeJ test with a head of 24 inches at a temperature of 70 F. through one of our improved valves of the dimensions above specified and through a straight taper needle valve of the same dimensions at seating and fully open points and of same stroke. On the left hand side of the'diagram we indicate the needle opening, the time in seconds required to pass -bureter as shown in Fig.y I under normal operating conditions, the relative proportion of fuel and air delivered is maintained by means of the curved taper needle valve and which, as stated, it has been the custom to attempt to overcome by means of a cam or lever mechanism for variably operating the needle valve in connection with the air valve and also adjustable springs have been used in conjunction with the air valve in an attempt to control the relative flow of air with the flow of fuel. These mechanisms have not been wholly satisfactory and we accomplish the superior results without the aid of the mechanisms previously used. With our improved carbureter a substantially uniformly proportioned mixture of air and fuel is supplied by the carbureter throughout the range of the engine speeds.

In the modified structure shown in Fig. IX the air valve is controlled entirely by the suction 'of the engine, that is it has no manual operating means. The fuel Valve 26 in this structure is carried by the short valve stem 27 beingV adjusted in the stem 'by means of the threaded plug 28 and held against the `plug by the spring 29. rIhe mechanism aside from the operating means for the valve is the same as that shown in Fig. I'. Thisembodiment is found to be very satisfactory.

V/'e have illustrated and described our improvements in two forms in which we have embodied the same in practice. -We have not attempted to illustrate or describeother embodiments which we contemplate as we believe the disclosures made will enable those skilled in the art to which this invention relates, to embody or adapt the same as conditions may require. We desire, however, to be understood as claiming our irnprovements specifically .in the form illustrated as well as broadly within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a carbureter, the combination o an. air valve, a fuel nozzle, and a fuel valve having a tapered needle point with an inward longitudinal curvature arranged for simultaneous actuation with said air valve and seating in said nozzle, the curve of the taper being the arc of a circle whose center is below a plane through the needle point and the valve seat when the fuel valve is fully opened.

2. In a carbureter, the combination of an air valve, a fuel nozzle, and a fuel valve having a tapered needle point for simultaneous operations with said air valve and seating in said nozzle, the curve of the taper being the arc of a circle whose center is adjacent a plane through the needle point and the valve seat when the valve is fully opened.

In witness whereof, we have hereunto set our hands and seals inthe presence of 'two witnesses.

WILLIAM SHKESPEARRJR. WLLLIAM SGHlllID.

Witnesses:

LUnLLA G. GREENFIEID, MARGARET L. GLASGOW.

Copies of this patent may be obtained for tlve cents each, by addressing the commissioner of Patents, Washington, D. 

